OSLO: Norwegian oil and gas company Statoil on Friday confirmed the deaths of three of its Norwegian employees at the In Amenas gas plant hostage-taking in Algeria, including the stepfather of a government minister.

Two other Norwegians who worked on the site at the time of the attack are still missing, it said in a statement.

"Our thoughts go out to the families and friends who lost loved ones in this horrible and senseless attack against innocent people," said the chief executive of Statoil, Helge Lund.

The three victims were identified as Hans Bjone, 55, Thomas Snekkevik, 35, and Tore Bech, 58, who is married to International Development Minister Heikki Holmaas' mother.

"We are a company in mourning," Lund said.

Earlier on Friday, the Norwegian foreign ministry said it was "unlikely" that the five would be found alive.

"From what we understand, the Algerian authorities continue to search on and around the plant but it's unlikely that any survivors will be found," a spokeswoman for the Norwegian foreign ministry, Veslemoey Lothe Salvesen, said.

Unlike countries like Britain, the Scandinavian country does not use the term "presumed dead."

But with hope of finding them alive fading, Oslo has sent a team of forensic experts to Algeria to help identify the dead.

All five were working for oil and gas company Statoil, one of the operators of the In Amenas gas plant, which was attacked by Islamist militants on January 16.

According to preliminary estimates by the Algerian authorities, 37 foreign hostages and 29 kidnappers died in the Islamist attack against the gas field and in the military operation that followed.